The present invention is related to a method for the operation of a wind energy plant with voltage-dependent control of a reactive electric variable which is to be provided, in which a desired value for the reactive electric variable is calculated.
Today's wind parks are required to be voltage-supportingly connected with the electric grid. It is therefore provided that a voltage-dependent reactive power is provided by the individual wind energy plants and/or by the wind park as a whole. This is also designated as an Automatic Voltage Regulation (AVR), and it serves to keep the voltage constant in the grid by providing reactive power and/or reactive current at voltage fluctuations which remain in certain ranges.
From EP 1 282 774, the entire contents of which is incorporated herein by reference, a method for the operation of a wind energy plant with a generator is known, which generates electric power for an electric supply grid. In the wind energy plant it is dealt with a pitch-controlled plant, the power of which is controlled and/or adjusted depending on the grid frequency. Further, it is known that the supplied power is reduced when the grid frequency exceeds a reference value for the grid frequency for more than 3%.
From EP 1 386 078, the entire contents of which is incorporated herein by reference, it is known to change the phase angle depending on the absolute value of a voltage detected in the supply grid. In this, the phase angle remains unchanged inside a dead band. When leaving the dead band, the absolute value of the phase angle, which describes the reactive portion of the power, is increased at rising or decreasing voltage.
From EP 1 508 951 A1, the entire contents of which is incorporated herein by reference, it is known to adapt the reactive power which is to be provided dynamically, depending on parameters of the wind energy plant.
The present invention is based on the objective to provide a method for the operation of a wind energy plant, in which can be reacted to voltage changes by providing a reactive electric variable in a time which is as short as possible.